Primers for polymerase chain reaction to amplify genomic DNA of both Toxocara canis and T. cati were constructed by adapting cloning and sequencing random amplified polymorphic DNA. The primers are expected to detect eggs and/or larvae of T. canis and T. cati, both of which are known to cause toxocariasis in humans.

Of the 2,652 Lymnaea truncatula collected from sites in Cumbria and Gwynedd during 1973–75, when the Prevalence of fascioliasis in the primary host was low and declining, only 123 were infected with Fasciola hepatica. Dissection of these snails revealed that the proportion infected, the mean redial burden and the Proportion of mature rediae in each snail increased with shell length.

The results are compared with a similar data set acquired when the prevalence of infection in both the Primary and intermediate hosts was uncharacteristically high. Although the results are qualitatively similar, there are important quantitative differences. The mean redial burden of infected snails at times of high disease Prevalence was generally twice as high as that reported in the present study. It is suggested that differences in habitat microclimate could not account entirely for the observed differences in redial burden and the role of multiple miracidial infection is discussed.

A cross-sectional study was carried out to investigate the prevalence and risk factors for severe anaemia among schoolchildren in New Halfa, eastern Sudan. After taking age and gender, haemoglobin (Hb) levels were measured and all children were screened for malaria and intestinal parasitic infections, including schistosomiasis. Six hundred and forty (230 boys, 410 girls) schoolchildren aged 8–18 years were enrolled. The mean (SD) of the haemoglobin was 9.6 (1.7) mg/dl. One hundred and eleven (17.3%) and 33 (5.2%) children had Schistosoma mansoni infection and Hymenolepis nana infection, respectively. Five hundred and eighty (90.6%) of these children had anaemia (Hb < 12 g/dl), and 103 (16.0%) of them had severe anaemia (Hb < 8 g/dl). Girls (OR = 2.5, 95% CI = 1.1–5.3; P = 0.01) were at higher risk for severe anaemia in univariate and multivariate analyses. Schistosoma mansoni infections were associated with severe anaemia in univariate analyses only. Thus, there was a high prevalence of severe anaemia among these children. This needs to be investigated in more depth in the future, and more attention should be paid to the health of adolescent girls.

Laboratory hamsters (Mesocricetus auratus) were infected with Echinostoma revolutum (Trematoda). Immunoelectrophoretic studies of hamster serum showed no demonstrable antibody response to E. revolutum. Histopathologic examination of intestinal tissue of infected hamsters showed erosion of intestinal villi and lymphocytic infiltration as the primary host response. Spleens from infected hamsters were hyperplastic during the first 3 weeks of infection and atrophic from 4 to 8 weeks postinfection. Hamsters were unable to acquire a resistance to E. revolutum infection. Lack of resistance was demonstrated in hamsters where the parasite infection was no longer detected based on the absence of eggs in the faeces; these hamsters were then reinfected. Hamsters treated with the anthelmintic oxyclozanide were also reinfected with E. revolutum.

Triploid, parthenogenetic forms of the lungfluke, Paragonimus westermani, occur in Japan, Korea and China. The origin(s) of triploidy has been debated over the years. Sequences of two regions in the mitochondrial DNA, i.e. partial lrRNA (16S), and a portion of the non-coding region, were obtained from natural populations of P. westermani. All triploid individuals (Japan, Korea, China) and a single tetraploid individual (China) had identical sequences in the 16S region studied. Some sequence variation was observed among diploids, with those from Taiwan being distinct from the remainder. Both neighbour joining and parsimony trees using the 16S region placed diploid individuals from southwestern Japan close to the triploids and the tetraploid. The fragment amplified from the mitochondrial non-coding region showed dimorphism. One form (type A) consisted of 239bp comprising two identical tracts of 70bp separated by a tract of 93bp. The second form (Type B) consisted of only a single 70bp tract. All diploid individuals from Taiwan, China and Korea possessed type A, while those from Japan were polymorphic; individuals from Oita and Hyogo had type B, those from Chiba had type A, but both types were found in Mie. On the other hand, all of the triploid individuals and two tetraploid individuals possessed type B. Both the form present in the non-coding region and the 16S sequence suggest an affinity between a south-eastern group of diploid populations in Japan and the triploid form. A possible mechanism responsible for the origin of the triploid is discussed.

In some investigations on skin penetration by the filariform larvæ of Strongyloides (Goodey, 1925), the writer made use of larvæ cultivated from the droppings of a Guinea Baboon, Papio papio, which had died at the Gardens of the Zoological Society of London. Scrapings of the lining of the small intestine of this animal were made so as to secure the parasitic worms of which 25 specimens were obtained. A study of these was undertaken because von Linstow's (1905) original description of the species is so slender and his figures illustrating it are so crude that it was considered that the parasite would repay further investigation. Moreover one or two of his statements as, for example, that the cuticle of the parasite females is unstriated, required critical examination. Again in a recent paper Chandler (1925) has thrown doubt on the specific identity of S. fülleborni, suggesting that it is probably a hostal variety of S. papillosus. For these reasons the present paper has been prepared in that it gives a fuller account of S. fülleborni both in the parasitic and in the free-living generation than has hitherto been available. The writer considers that a detailed and well illustrated account of the morphology of S. papillosus, particularly of the free-living, sexual generation, is much needed at the present time.

A Preliminary outline of the life history of the lungworm of the cat and its confusion with that of Ollulanus tricuspis, has been given in a previous paper. Since that paper was published, the name of the family of lungworms has been changed to Protostrongylidæ by Professor Leiper; and an examination of adults of the lungworm from the cat, shewed that it belonged to a different genus from the type of the old genus Synthetocaulus. To this new genus, the name ælurostrongylus has been given.

The sensitivities of the Knott's test (four 20-μl sediment aliquots), quantitative buffy coat capillary tube method (QBC tube, 111 μl of whole blood) and direct blood smear (DBS, 20 μl of whole blood) were evaluated for the detection of microfilaraemia in dogs. Undiluted whole blood samples taken from 70 Dirofilaria immitis antigen-positive dogs and 10 serially diluted microfilaraemic blood samples at concentrations of 400, 200, 100, 50, 25 and 12 microfilariae (mff) ml−1 were examined. For filarial speciation, the buffy coat of QBC tubes was mixed with one drop of methylene blue–formalin solution and examined as a direct smear. In 52/70 microfilaraemic blood samples, the number of mff ranged from 12 to 321987 ml−1 (median: 3199 ml−1). The diagnostic sensitivity of the Knott's test, QBC tube method and DBS in undiluted blood samples attained the 100%, 98% and 92.3% levels, respectively. Eighteen dogs tested amicrofilaraemic by all three methods. At concentrations of 400 mff ml−1, a 100% sensitivity was found by all three methods, while at 200 mff ml−1 the Knott's test, QBC tube and DBS were 100%, 100% and 90% sensitive, respectively. The relevant figures at 100 mff ml−1 were 100%, 100% and 80%, at 50 mff ml−1 100%, 100% and 50%, at 25 mff ml−1 100%, 100% and 10% and at 12 mff ml−1 80%, 50% and 10%. At 50 and 25 mff ml−1, the DBS was less sensitive compared to the other two methods, while at 12 mff ml−1, only to the Knott's test. A significant correlation was found between the QBC tube method and Knott's test regarding mff speciation. Therefore, the QBC method may be considered a reliable alternative to the Knott's test for both the detection and speciation of mff in the dog.

Cyst wall, brood capsules and evaginated protoscoleces of E. granulosus (ovine and equine) and E. multilocularis were fixed in 10% formol-saline embedded in paraffin and cut at 8 μm. Specific rabbit antisera to antigen 5 and antigen B of hydatid cyst fluid were used with immunoperoxidase methods to localise the antigens in the histological sections.

Antigen 5 was found in all parasites and was associated with cells of the subtegumental area of the protoscolex, the brood capsule wall and the germinal membrane. The labelled antigen appeared as distinct granules in all areas. It is suggested that antigen 5 may be synthesised in all of these sites and that a source of the antigen in cyst fluid may be the germinal and brood capsule membranes. The laminated membranes of E. granulosus (ovine and equine) were, except for the superficial layers, free from antigen 5.

Antigen B was present in all parasites. It was distributed diffusely throughout the laminated membrane, germinal membrane and brood capsule wall. There were areas of densely labelled antigen B on the surface of the distal cytoplasm of the protoscolex tegument and the surface of calcareous corpuscles. The distribution of antigen B in relation to PAS positive meterial and possible complement activating substances is discussed.

The laminated membrane of E. granulosus was apparently more permeable to antigen B than to antigen 5. It is suggested that differences in the diffusion of these antigens through the laminated membranes of hydatid cysts in the same or different host species may account for variable serological responses during infection.

Paramphistomum explanation, Gastrothylax crumenifer, and Fasciola gigantica were maintained for periods of twelve hours in a non-nutrient medium containing streptomycin and penicillin to prevent bacterial growth. They were kept under aerobic conditions at a suitable temperature of 37%C. The protein content in P. explanatum ranged from 50·0% to 54·7% with an average of 52·96%±0·23 of the dry weight of the tissue. In G. crumenifer it ranged from 43·5% to 51·5% with an average of 48·8%±0·56 of d.w.t. In F. gigantica it ranged from 63·8% to 68·3% with an average of 66·5%±0·26 of d.w.t. The nitrogen content of the P. explanation excreted as ammonia after a starvation period of twelve hours was 3·95% and as uric acid it was 0·077%. In G. crumenifer the ammonia was 2·91% and uric acid 0·033%. In F. gigantica ammonia was 2·51% and uric acid 0·1%.

An epidemiological survey was undertaken of anisakids in 139 specimens (length: 13.2–24.5 cm) of pouting or bib (Trisopterus luscus) captured off the coast of northern Spain in the Cantabrian Sea. Third-stage larvae of two species of nematodes, Anisakis larvae type I and Hysterothylacium aduncum, were isolated. One adult female H. aduncum was also detected in the intestine of one pouting. Total prevalence of anisakids was 88.5%. Hysterothylacium aduncum and Anisakis showed, respectively, prevalence of 87.8% and 22.3%, mean intensity of 19.7 and 3.5, and mean abundance of 17.3 and 0.8. Analysis of infection parameters as a function of host length revealed a much higher prevalence in pouting specimens with length < 20 cm (94.4% for H. aduncum; 28.0% for Anisakis) than in those with length ≥ 20 cm (65.6% for H. aduncum; 3.1% for Anisakis). The high mean intensity of Anisakis in muscle of parasitized pouting (5.9) may pose human health risks, although these are minimized by eating only thoroughly cooked pouting, as is the custom in Spain.

Experimental infections of Galba sp. (origin, Colombia) with allopatric isolates of Fasciola hepatica from France or Fascioloides magna from the Czech Republic were carried out during five successive snail generations to determine if this lymnaeid might sustain complete larval development of either parasite. In snails exposed to F. hepatica, 7 of 400 snails harboured several rediae and only two snails contained a small number of free cercariae on day 50 post-exposure. In contrast, the intensity of F. magna infection in Galba sp. progressively increased from the F1 to F5 generations. Spontaneous cercarial shedding of F. magna occurred in 7 of 100 Galba sp. belonging to the F5 generation and the number of shed cercariae did not differ significantly from that noted in control Galba truncatula of French origin. Galba sp. from Colombia can be added to the list of potential intermediate hosts for F. magna.

Eighty-seven red foxes were investigated for the presence of Toxocara eggs on a sample of their hair from the peri-anal region. The worm burden of Toxocara in each fox intestine was also assessed and the relationship between eggs on the hair and worms in the intestine explored. Twenty-eight per cent of the foxes were found to have Toxocara eggs on their hair, with an average of 1.31 ± 3.21 eggs per gram of hair ( ± SD). Sixty-one per cent of foxes harboured Toxocara worms within their intestines, with a mean worm burden ( ± SD) of 4 ± 8. Host age and sex did not significantly influence the observed eggs on the hair or the worm burden. No significant correlation was found between the numbers of eggs on the hair and the worm burden within the intestine. These data collected from foxes are explored in the context of data from stray dogs and the possible epidemiological differences are discussed.

Twenty-three adults (only one male) and two fourth-stage larvae of Anisakis, recovered from the stomach of a Blainville's beaked whale (Mesoplodon densirostris) stranded in Galicia (NW Spain), were studied morphologically and molecularly. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and sequencing studies carried out on the ribosomal DNA spacers and on the cox2 mitochondrial gene confirm that these nematodes belong to the taxon Anisakis sp. A, which was previously detected as a larval stage in fishes from Madeiran waters. In addition, our molecular studies demonstrate that Anisakis sp. A and the taxon Anisakis sp., previously found in other Mesoplodon spp., are the same species. The adults of Anisakis sp. A are morphologically similar to A. ziphidarum but with a shorter body length and longer spicules (right spicule 2.42 mm, left spicule 2.30 mm). Since the poor condition of the male tail cuticle prevented a proper description of the caudal plates and the pattern of caudal papillae, we propose to retain the name Anisakis sp. A until new males are described correctly.

The nematode Anisakis simplex causes anisakidiasis, a disease that often mimics other gastrointestinal diseases. Patients with digestive haemorrhaging, Crohn's disease, digestive cancer and appendicitis were analysed for antibodies to A. simplex. Antibody detection was carried out by enzyme-linked immunosorbent assay (ELISA) and immunoblotting using crude extract (CE) antigen and excretory-secretory (ES) products. Total immunoglobulin (Igs), IgG, IgM, IgA and IgE were studied. The highest percentage was obtained when Igs were tested against CE antigen. A higher percentage of positivity was observed with the appendicitis group. The Crohn's disease group showed the highest levels of IgG against the ES antigen. Using immunoblotting, 24% and 48% of sera from patients with symptoms of Crohn's disease and digestive haemorrhaging, respectively, showed a positive immunorecognition pattern of CE antigen. The prevalence of detectable antibodies against A. simplex is higher in patients with digestive disorders than in the healthy population. A linear correlation was observed between prothrombin activity and Igs-CE, IgA-CE and IgA-ES but not between IgE-CE and the other immunoglobulin levels. Specific IgA is associated with a higher activity index of Crohn's disease. Specific antibodies were observed against A. simplex in patients with appendicitis and gastrointestinal cancer, indicating a higher rate of positivity for IgA.

Plectus murrayi n. sp. is distinguished from other species by possessing 12 lips; stoma, amphid and excretory system are ‘plectoid’ rather than ‘anaplectoid’. Eudorylaimus antarcticus (Steiner, 1916) n. comb. is proposed for Dorylaimus antarcticus Steiner, 1916 and the species is redescribed. Both species were collected from mosses from the McMurdo Sound Region, Antarctica. Anaplectus arenicola Killick, 1964 has only six lips; stoma and excretory system are ‘anaplectoid’.

In a previous publication the morphological characters of a strain of H. schachtii specialised on the potato in Lincolnshire were discussed. The size and shape of the brown cysts, size of the eggs and first stage larvæ and the general characters of the adult males of this strain were compared with those of a strain attacking potatoes in Rostock, Mecklenburg, for which the specific name H. rostochiensis was suggested by Wollenweber 1923.

Considerable dimensional variations were found to exist in the Lincolnshire strain, and a study of the literature on the morphological characters of H. schachtii specialised on sugar-beet and oats, showed equally wide divergencies between the findings of different workers. A certain amount of preserved material of infected roots of beet and oats being available to the writer, as many developmental stages as possible were extracted from these, on which similar morphological studies were carried out. Thus a fairly complete comparative survey of H. schachtii specialised on beet, oats and potatoes was completed, and the morphological variations between the strains were found to be insufficient to justify the separation of the strain specialised on potato from those on beet and oats. The name H. rostochicnsis was, therefore, deemed a synonym for H. schachtii.

The role of the red fox Vulpes vulpes in the dissemination of eggs of Toxocara canis into the environment is considered with reference to female worm fecundity and egg output in the faeces of infected foxes collected from four localities in southern England. A significant positive correlation was found between female worm size and the number of eggs in the uterus but there was no significant relationship between T. canis worm numbers and egg output in fox faeces. Reliable estimates of worm burdens in foxes could not, therefore, be determined from faecal egg counts alone. The highest mean egg output of 2145.0 epg recorded from adult foxes indicated that fox cubs are not necessarily the main sources of environmental contamination with T. canis eggs. Saturated magnesium sulphate was found to be a more effective flotation solution than zinc sulphate and sodium chloride for recovering eggs from fox faecal samples.

The family Clinostomidae Lühe, 1901 contains 29 species allocated to seven genera, of which Clinostomum Leidy, 1856 is the most diverse, with c. 14 valid species. The diversity of Clinostomum has been assessed, combining morphological and molecular data. The genetic library for species in this genus has increased steadily, although there is little or no information for the other genera included in the family. Molecular phylogenetic relationships among the genera of clinostomids have not been assessed, and their classification is still based on morphological traits. The monotypic Ithyoclinostomum was described from a fish-eating bird in Brazil, and its metacercariae have been found in several locations in South America, parasitizing erythrinid freshwater fishes. We collected unusually large metacercariae from the body cavity of cichlids in several locations across Middle America. These metacercariae exhibited some resemblance to Ithyoclinostomum, although several differences prevent their inclusion in Ithyoclinostomum dimorphum, casting doubt on their taxonomic identification. The main objective of this paper was to characterize the metacercariae collected in cichlids using both morphology and molecular data from three molecular markers, and to assess the molecular phylogenetic relationships among the genera of Clinostomidae to establish the position of the newly generated sequences. We took a conservative position and tentatively placed the metacercariae as belonging to Ithyoclinostomum.

The Asian fish tapeworm, Schyzocotyle acheilognathi (syn. Bothriocephalus acheilognathi) represents a threat to freshwater fish, mainly cyprinids, across the globe. This tapeworm possesses an extraordinary ability to adapt to different environmental conditions and, because of that, from its natural geographical origin in mainland Asia, it has colonized every continent except Antarctica. It is thought that this pathogenic tapeworm was first co-introduced into Mexico in 1965 from China, with the grass carp Ctenopharyngodon idella, although the first formal record of its presence was published in 1981. Over the past 35 years, the Asian fish tapeworm has invaded about 22% of the freshwater fish in Mexico. Because fish communities in Mexico are characterized by high species richness and levels of endemism, S. acheilognathi is considered as a co-introduced and co-invasive species. In this review, we update the geographic distribution and host spectrum of the Asian fish tapeworm in Mexico. Up until December 2016, the tapeworm had been recorded in 110 freshwater fish species (96 native and 14 introduced), included in 51 genera, 11 families and 4 orders; it was also widely distributed in all types of aquatic environments, and has been found in 214 localities. We present novel data from a survey aimed at establishing the distribution pattern of the tapeworm in native freshwater fishes of two rivers in north-central Mexico, and the genetic variation among individuals of this co-invasive species collected from different host species and localities. We discuss briefly the factors that have determined the remarkable invasive success of this parasite in freshwater systems in Mexico.